N. Ganga Devi

Bio: N. Ganga Devi is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Acrylonitrile & Polymerization. The author has an hindex of 4, co-authored 4 publications receiving 57 citations.

Redox polymerisation. Kinetics of the reaction initiated by the malonic acid/Mn3⊕ system

Abstract: Kinetics of vinyl polymerisation initiated by the redox system malonic acid/Mn3⊕ have been investigated in the temperature range of 5-15°C in sulphuric acid and perchloric acid media for acrylonitrile and methyl methacrylate. A mechanism involving the formation of a complex between Mn3⊕ and malonic acid whose decomposition yields the initiating free radical with the polymerisation being terminated by mutual interaction of growing radicals has been suggested. Es wurde die Reaktionskinetik der durch das Redoxsystem Malonsaure/Mn3⊕ initiierten Vinylpolymerisation von Acrylnitril und Methylmethacrylat im schwefelsauren und perchlorsauren Medium im Temperaturbereich von 5-15°C untersucht. Es wird ein Mechanismus vorgeschlagen, welcher die Bildung eines Komplexes zwischen Mn3⊕ und Malonsaure vorsieht. In dem vorgeschlagenen Mechanismus wird das Startradikal durch Zerfall des Komplexes gebildet, und die Abbruchreaktion erfolgt durch eine Radikalkettenabbruchsreaktion der wachsenden Polymerketten.

Redox polymerization of acrylonitrile‐kinetics of the reaction initiated by the redox system dimethyl sulfoxide–Mn(III)

Abstract: The kinetics of oxidation of dimethyl sulfoxide by tervalent manganese was investigated in sulfuric and perchloric acid media at 40–45°C. A mechanism involving prior complexation between reactants followed by a reversible electron-transfer step was shown to be consistent with the kinetics. The radical ion thus produced initiates polymerization of acrylonitrile, the termination being effected by the oxidant. Rates of polymerization vary directly as the sulfoxide concentration and are proportional to the square of the monomer concentration and being independent of the oxidant. Oxidation as well as polymerization is retarded by Mn(II). Average degrees of polymerization lend support to the proposed mechanism. Rate parameters have been evaluated in the two media, and their significance is discussed.

Redox polymerisation, 2. Kinetics of the reaction initiated by the system cyclohexanone/Mn(III)

Abstract: Polymerisation of acrylonitrile and methyl methacrylate initiated by the system cyclohexanone/Mn(III) has been investigated at 30–35°C in perchloric acid and sulphuric acid media The kinetics are consistent with the formation of an intermediate complex between the ketone and the oxidant whose decomposition leads to the initiating radical In perchloric acid the termination is effected by the oxidant whereas in sulphuric acid primary radicals terminate growing chains Rate and equilibrium constants have been determined and their significance discussed Die durch das System Cyclohexanon/Mn(III) angeregte Polymerisation von Acrylnitril und Methylmethacrylat wurde bei 30–35°C in perchlorsaurem und schwefelsaurem Medium untersucht Die Kinetik last sich mit der Annahme der Bildung eines Komplexes zwischen dem Keton und dem Oxidans als Zwischenstufe vereinbaren, dessen Zerfall die startwirksamen Radikale liefert In Perchlorsaure erfolgt der Kettenabbruch durch das Oxidans, wahrend in Schwefelsaure die Primar-Radikale fur den Abbruch der wachsenden Ketten verantwortlich sind Geschwindigkeits- und Gleichgewichtskonstanten wurden bestimmt, und ihre Zuverlassigkeit wurde diskutiert

A Comprehensive Simulator/Database Package for Reviewing Free-Radical Homopolymerizations

Abstract: Several models have been proposed in the literature over the last two decades in order to simulate free-radical homopolymerizations. However, most of these models deal with one specific monomer system, usually under restricted polymerization conditions.

Agricultural polymers polyacrylamide preparation, application and prospects in soil conditioning

Abstract: This reviews 509 articles via 505 refs. cover the period 1906–80. It surveys acrylamide preparation, polymerization by radiation and handling. A cheap method for PAM production is prospected. Chemical and technological means of solving tillage problems, soil reclamation and arable land creation are reviewed. The role of PAM on soil physico‐chemical properties, irrigation requirements and crops yield is discussed. Modification of PAM for imparting chemical and bacteriological fertilities besides conditioning soils is also prospected. This possibly creates cheaply arable fertile lands.

Redox Polymerization Initiated by Metal Ions

Abstract: During the last four decades there has been rapid development of the use of redox systems [1–30], that is, systems containing both an oxidizing and reducing agent, for the initiation of vinyl polymerization. Polymerizations which are initiated by the reaction between an oxidizing and a reducing agent may be called redox polymerizations.

Grafting of Vinyl Monomers onto Wool Fibers

Abstract: Chemical modifications have been devised to give natural macro-molecules more desirable properties, and the application of synthetic macromolecules forms an important area of such chemical modification. The literature abounds with the examples of successful formation of copolymers from natural and synthetic macromolecules. The molecular architecture of the natural substrate is not affected by the presence of polymer, but the nature of the polymer formed in the environment of a natural substrate may be quite different from the homopolymer formed under similar polymerization conditions.

Modeling the Effects of Reactor Backmixing on RAFT Polymerization

Abstract: The effects of reactor backmixing on the outcome of RAFT polymerizations are examined. The kinetic model for the RAFT reaction is based on the first principle of mass balances and the method of moments. Two reactor models were applied for the simulation of backmixing, i.e., a PFTR with loop and multiple CSTRs in series. The models predict the behavior of monomer conversion, molecular weights, their distributions as well as the polydispersities for various chain types at different levels of backmixing. Both models demonstrated that a significant impact of reactor backmixing on RAFT kinetics and polymer molecular weight development exists. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.